If you build a robot using methods that mimic the human body does it make it more likely to move like a human? It seems it does and, what is more, the effect is unsettling.

The uncanny valley is an effect where robots that are close to humans in appearance and behavior aren't quite good enough to fool us and so we feel uncomfortable with them. We don't make allowances for them as we do with robot vacuum cleaners, but they don't quite make it into the "human" category either.

IEEE Spectrum has a report and a video of the work of researchers at the University of Tokyo on their latest musculosketal robot, Kenshiro. This follows the design of the human body - its bones and muscles and, as important, its joints. The design is as anatomically correct as it needs to be to provide the same degrees of freedom and control as the human machine.

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It works with 160 "pulley-based" muscles that provide the contraction forces similar to real human muscles - remember muscles pull and don't push.  The bones and joint are engineered in Aluminum and have anatomical details like the cruciate ligament in the knee and a floating paella - knee cap to you and me.

Is it worth so much fidelity?  Watch the video and see what you think:

The early parts of the video make interesting watching, but somehow the spookyness of the whole thing increases as more and more movements are added to the demonstration. The knee bending is the moment where most viewers start to express their uneasiness. Seeing something that is clearly a machine move like a human does seem to be enough to put it into the uncanny valley. What would happen however if it was to acquire a skin, not to mention a head? Would it be convincing enough?

It is also clear that, if you don't want robots to walk and move as if they were pieces of machinery, copying the skeletal structure of a human is a good way to start.